Lubrication of internal combustion engines



Oct. 18, 1955 c. P. AMBLER LUBRICATION OF INTERNAL COMBUSTION ENGINES 4 Sheets-Sheet 1 Filed Nov. 4, 1954 .WEAR RATE wmIO7:

Oct. 18, 1955 c. P. AMBLER LUBRICATION OF INTERNAL COMBUSTION ENGINES 4 Sheets-Shee t 2 Filed Nov. 4, 1954 WHIOZ uxomkm Oct. 18, 1955 c. P. AMBLER LUBRICATION OF INTERNAL COMBUSTION ENGINES 4 Sheets-Sheet 3 Filed NOV. 4, 1954 mdDOI Oct. 18, 1955 c. P. AMBLER 2,720,942

LUBRICATION OF INTERNAL COMBUSTION ENGINES Filed Nov. 4, 1954 4 Sheets-Sheet 4 A, an,

United States Patent LUBRICATION OF INTERNAL COMBUSTION ENGINES Cecil P. Ambler, Mooretown, Ontario, Canada, assignor to Polymer Corporation Limited, Sarnia, Ontario, Canada, a corporation of Canada Application November 4, 1954, Serial No. 466,932 Claims priority, application Canada September 30, 1954 4 Claims. (Cl. 184-18) This relates to a new and improved system of lubricating the cylinders of internal combustion engines of the conventional type having at least one cylinder, a piston reciprocable therein, a crankshaft connected to said piston, and a plurality of piston rings fitted about said piston.

A common problem with regard to internal combustion engines is cylinder wear, particularly uneven cylinder wear which causes the cylinder to become out-of-round and which greatly aifects the compression of such engines. This is especially true of stationary internal combustion engines which are often subjected to long periods of sustained operation and are often operated on low-grade fuels.

It is, therefore, an object of the present invention to provide for the cylinders of an internal combustion engine a lubricating system which greatly reduces cylinder wear.

It is also an object of the present invention to provide for the cylinders of an internal combustion engine a lubricating system which reduces not only cylinder wear but also that uneven wear which results in the cylinders becoming considerably out-of-round.

In the past, various lubricating systems have been devised wherein a lubricant is injected into cylinders. It has always been realized that leakage of the lubricant into the upper cylinder must be minimized, and the prior systems call for the lubricant to be injected into the cylinders below the level of the top piston ring when the piston in the cylinder is in the bottom dead centre position. It has now been found, however, that a substantial proportion of cylinder wear is attributable to carbonaceous deposits on the uppermost piston ring which increase the friction between such ring and the cylinder wall and that such wear is not appreciably reduced by these prior systems. The effect of such deposits on the uppermost piston ring appears to have been overlooked in these prior systems.

Furthermore, such prior systems have concentrated on injecting the lubricant into the cylinder at the point of greatest mechanical thrust, i. e. 90 to the axis of the crankshaft, although, surprisingly, the greatest wear in the cylinders of an internal combustion engine is substantially parallel to the crankshaft axis rather than at 90 thereto.

According to the present invention, a method of lubri eating an internal combustion engine comprises injecting lubricant through the wall of each cylinder at opposing points lying substantially in the diametric plane of said cylinder in which the crankshaft axis lies, said points heof each cycle.

In the present specification, the uppermost piston ring is deemed to be that farthest from the crankshaft irrespective of whether the crankshaft is normally below the piston or not.

2,720,942 Patented Oct. 18, 1955 In the accompanying drawings, which illustrate the preferred embodiment of the present invention:

Figure l is a graph illustrating cylinder wear in an engine lubricated by existing standard methods (i. e. using no cylinder wall injection of lubricant) Figure 2 is a graph illustrating cylinder wear in an engine lubricated according to the present invention.

Figure 3 is a graph illustrating cylinder wear of an engine lubricated according to the present invention in relation to cylinder wear in an engine lubricated by existing standard methods.

Figure 4 is a cross-section of an engine illustrating a lubricating system according to the present invention.

Although the present invention is applicable to internal combustion engines burning any of the standard fuels, the most startling results are obtained "when it is applied to engines burning low-grade fuels. Tests carried out in connection with the present invention employed stationary internal combustion engines burning low-grade fuel, and the graphs illustrated in Figs. 1, 2 and 3 are compiled from data obtained in tests employing such stationary engines. Thus, while the details given in the following description mainly concern stationary internal combustion engines burning low-grade fuels, it should be understood that the description will equally apply to all internal combustion engines utilizing hydrocarbon fuels.

Figure l is illustrative of the cylinder wear which may be expected in an internal combustion engine. Line A represents the cylinder wear in a direction parallel to the crankshaft while the line B represents cylinder wear in a direction normal to the crankshaft. The axis of ordinates is graduated in inches of the piston strokes. The axis of abscissae represents cylinder wear in thousandths of an inch per thousand hours.

It will be noted that the wear parallel to the crankshaft (that represented by line A) is substantially greater than the wear at right-angles to the crankshaft, especially in the upper part of the cylinder. Results show that at the end of the test run, which lasted for a period of 12,576 hours, the cylinders were considerably out-ofround. It also established a trend which, if it had been allowed to continue, would have resulted in worn-out cylinders after 260,000 hours.

When, according to the present invention, oil was injected into each cylinder at two substantially diametrically opposed points lying on a line parallel with the crankshaft of the engine and situated so that the points of injection are covered by the uppermost piston ring when the piston reaches the bottom dead centre position, the cylinder wear was reduced to the point illustrated in Figure 2.

Figure 2 is a graph compiled from data obtained in a test run carried out with an engine similar to that which provides the data in Figure l. The engine on this occasion was test-operated over a period of 11,277 hours. i It will be noted from the graph shown in Figure 2 that the to the crankshaft and that normal to the crankshaft is insignificant.

The improvements achieved by a system of lubricating the cylinders of an internal combustion engine according to the present invention are, perhaps, most clearly illustrated by the graph shown in Figure 3. The line A represents the total wear of the cylinders of an engine having an orthodox system of lubrication while the line B shows the total wear of the cylinders of an engine lubricated according to the present invention. C represents the anticipated normal rate of wear assuming favourable operating conditions. This graph clearly illustrates that the present lubricating system not only counteracts the effects of low-grade fuel with regard to cylinder wear, but also considerably reduces cylinder Wear in comparison to the normal rate of wear;

7 Figure 4 illustrates an actual embodiment of the present system of lubrication. Although only two cylinders are illustrated, additional cylinders maybe lubricated merely by the extension of the main lubricant-feed line.

In each of the cylinders 1 of an internal combustion engine are provided two opposing orifices2 and 3 which lie substantially in the diametric plane of each cylinder 1 in which lies the axis of the crankshaft of the engine. Orifices ,2 and 3 are disposed at a depth in each cylinder 1 so as to be just covered by the uppermost piston ring 4 when the piston 5 in each cylinder 1 reaches the bottom dead centre position. This latter position is indicated in the left-hand cylinder in Figure 4.

Needle valves 6 and 7 are installed one in each of the orifices 2 and 3. Extending from each of the needle valves 6 and 7 are branch oil feed lines 8 and 9 respectively which tap a main feed line 10. The main oil feed line 10 is common to the branch feed lines 8 and 9 of both the cylinders 1 and'is supplied with lubricant under. pressure by the main oil pump 11 of the engine which also supplies the bearings oi the engine with lubricant. It is considered highly advisable to supply the main feed line 10 from the main oil pump 11 rather than from a separate oil pump which would normally be of lower power.

The later has been used with disadvantage in prior systerns of direct cylinder lubrication.

It is preferable that an oil filter 12 be located in the main feed line 10 intermediate the pump 11 and the first branch feed line 9.

In order to provide individual adjustment to the lubrication of each cylinder 1, throttle valves 13 are provided in each of the branch oil feed lines 8 and 9 intermediate the needle valves 6 and 7 and the main oil feed line I0. The throttle valves 13 permit flexibility and a generous range in the rate of flow of lubricant to each of the cylinders 1. Since the orifices 2 and 3 are covered by the uppermost piston ring 4 of the piston 5 of each cylinder 1 when the piston 5 is in the bottom dead centre position,

the uppermost piston ring 4 is washed with lubricant every time the piston 5 is in this position. This greatly reduces carbon deposits and accordingly reduces cylinder wear.

The cylinders of an engine having a lubricating system according to the present invention will tolerate a liberal flow of lubricant without any ill effects on performance. It has been found that an oil feed rate of one Imperial pint per hour through each orifice 2 and 3, or, in other words, one Imperial quart of oil per hour gives "ery satisfactory results. The oil injected into each cylinder 1 drains therefrom into the crank case of the engine (not shown) and from there it is recirculated by the main oil pump 11. The oil 'is then pumped from the crank case through the filter 12 and again to the cylinders 1 by the main oil pump'll.

What I'claim is:

1. An internal combustion engine having at least one cylinder, a piston reciprocable therein, a crankshaft connected to said piston, and a plurality of piston rings fitted about said piston, comprising a lubricant pressure source, means for feeding lubricant from said pressure source to two opposing orifices formed in the inner wall of each cylinder, said orifices lying substantially in the diametric plane of said cylinder in which the crankshaft axis lies, and said orifices being coveredby the uppermost piston ring when said piston isin the bottom dead centre position.

2. An internal combustion engine as claimed in claim 1 in which said means for feeding lubricant from said'lnbricant pressure source to said orifices comprises a main feed line and a plurality of branch feed lines, said branch feed lines being connected each between one of said orifices and said main feed line, and said main feed line being connected between said branch feed lines and said lubricant pressure source.

3. An internal combustion engine as claimed in claim 1 in which said lubricant pressure source is the main oil pump of said engine.

4. An internal combustion engine having at least one cylinder, a piston reciprocable therein, a crankshaft connected to said piston, and, a plurality of piston rings fitted about said piston, comprising an oil pump, two opposing apertures formed in the wall of each cylinder, at least two needle valves, a main feed line, at least two branch feed lines, an oil filter and at least two throttle valves, said needle valves being installed each in one of said apertures, said apertures lying substantially in the diametric plane of said cylinder in which the crankshaft axis lies, said apertures being covered by the uppermost piston ring when said piston is in the bottom dead centre position, said branch feed lines being connected each between one of said needle valves and said main feed line, said main feed line being connected between said branch feed lines and said oil pump, said oil pump being'the main oil pump of said engine, said filter being connected in said main main feed line intermediate said branch feed lines and 7 said oil pump, and said throttle valves being connected one in each branch feed line.

References ited in the file of this patent UNITED STATES PATENTS 1,643,674

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